GIS支持下CF与Logistic回归模型耦合的九寨沟景区滑坡易发性评价

LANDSLIDE SUSCEPTIBILITY ASSESSMENT IN JIUZHAIGOU SCENIC AREA WITH GIS BASED ON CERTAINTY FACTOR AND LOGISTIC REGRESSION MODEL

2017年8月8日九寨沟MS7.0地震诱发了数以千计的崩滑体,产生的大量松散固体碎屑在降雨作用下极易启动转化为新的滑坡或泥石流形成次生灾害,因此对九寨沟景区进行滑坡易发性评价尤为必要。基于震前、震后高精度遥感影像对比分析结合现场调查,共获取1047处滑坡,总面积为3.88 km2。在分析滑坡发育分布与影响因素关系的基础上,本文选取了构造因子、地形因子、地质因子及其他因子等9个指标,采用确定性系数(CF)模型、逻辑回归(Logistic)模型以及两种模型耦合分析进行滑坡易发性评价。研究结果表明,坡度、坡向、高程和地层岩性是影响滑坡分布的主要因子;研究区被划分为低易发区(60.72%)、中度易发区(24.18%)、高易发区(9.89%)和极高易发区(5.21%),高-极高易发区基本沿沟谷分布,面积为99 km2,其中熊猫海、老虎海周边均为滑坡极高易发区;采用耦合模型比单一模型评价结果更加合理,其结果可作为景区滑坡防治和分段分时开放的参考依据。

Thousands of coseismic landslides were induced by the Jiuzhaigou MS7.0 earthquake on August 8th 2017,Sichuan,China.Thus,a tremendous volume of loose debris are extremely prone to convert into landslides and debris flow under rainfall.Therefore,it is necessary to conduct landslide susceptibility assessment in Jiuzhaigou Scenic area.Based on a large set of pre-and post-earthquake high-resolution satellite images and field investigation,a polygon-based interpretation of the coseismic landslides is carried out.In total,1047 landslides are identified,covering an area of 3.88 km2.The relationship between the spatial distribution of landslides and its influencing factors is analyzed.Nine factors including tectonic,topographic,geological and other factors are selected to evaluate the landslide susceptibility by certainty factor model and logistic regression model,as well as coupled model.The result shows that slope,aspect,elevation and lithology are the main factors controlling the spatial distribution of landslides.The susceptibility of landslide is divided into low(60.72%),moderate(24.18%),high(9.89%)and extremely high areas(5.21%).The high and extremely high areas covering an area of 99 km2 including Tiger Lake and Panda Lake are distributed along the valleys.The assessment result of the coupled model is more reasonable than that of the single model and can be used as scientific reference for prevention of landslide hazard and segmented opening time of scenic area.